Atherogenic index of plasma as a novel predictor for acute kidney injury and disease severity in acute pancreatitis: a retrospective cohort study

Background The atherogenic index of plasma (AIP) can be used to reveal atherosclerosis. This study evaluated the AIP's efficacy in predicting the prognosis of acute kidney injury (AKI) and severity of acute pancreatitis (AP). Methods This retrospective cohort study recruited AP cases from the First College of Clinical Medical Science of China Three Gorges University between January 2019 and October 2023, including 1470 patients. AIP was computed using the formula: log10 [serum triglyceride (mmol/L)/serum high-density lipoprotein cholesterol (mmol/L)]. The AIP relationships with AKI occurrence and AP severity were validated using multivariable logistic regression models, subgroup and sensitivity analyses, and curve fitting. Results Among the 1470 patients with AP, 250 (17%) developed AKI and 166 (11.3%) with severe AP. AIP was positively correlated with AKI and the severity of AP. Potential confounders were adjusted, consequently, AIP was positively linearly related to AKI (P for non-linearity: 0.731, OR 2.5, 95% CI 1.31-4.77,) and the severity of AP (P for non-linearity: 0.145, OR 3.1, 95% CI 1.53-6.27), respectively. The strength of the association between AIP and AKI, along with the severity of AP, was demonstrated through stratified analyses. Significant interactions were not observed in sex, age, hypertension, BMI, diabetes mellitus, SOFA score, BISAP score, and etiology of AP (all P for interaction > 0.05). The areas under the curves for AIP in predicting the incidence of AKI and severity of AP were 0.64 and 0.65, respectively. Conclusions This is the first study to suggest that the AIP is critical for the assessment of AKI risk, recommending early screening of severity among AP cases. Due to the observational nature of the study, the potential for residual confounding, and the need for external validation in larger, independent cohorts.